Frequently Asked Questions (FAQ)
The Thalidomide tragedy
What is Thalidomide?
Thalidomide is the active ingredient in a sleep aid and sedative that was sold by Grünenthal and its licence and distribution partners in many countries between October 1957 and November 1961. In Germany, it was marketed under the brand name Contergan, while in other markets it was sold under names such as Distaval (United Kingdom, Australia and others) or Softenon (Austria and Switzerland).
What was the Thalidomide scandal or tragedy?
Thalidomide was a sleep aid and sedative sold in many countries worldwide. In Germany, the drug was sold between 1957 and 1961 under the name Contergan and other brands. The medication was also taken by women for morning sickness during pregnancy because doctors found Thalidomide to have a positive effect. However, Grünenthal itself did not promote taking the medication for morning sickness. In November 1961, it became known that the drug caused severe deformities in newborn children if taken between the 34th and 50th day of pregnancy, counting from the first day of the last menstrual cycle.
The fate of the, what became known as, ‘Thalidomide babies’, and subsequent court proceedings, in Germany are still known today as the ‘Contergan scandal’ or ‘Contergan tragedy'.
Under what names was Thalidomide marketed?
The brand names varied by country: In Germany, Thalidomide was marketed by Grünenthal under the brand name Contergan. In other countries, licensing and distribution partners also marketed Thalidomide-containing drugs under other names, such as Distaval in the United Kingdom and Softenon in Austria and Switzerland.
In which countries was Thalidomide sold?
Grünenthal's distribution partners and licensees sold medicines containing Thalidomide in many countries around the world. The products were marketed under various brand names, such as Distaval and Softenon. In addition, companies sold medicines containing the active ingredient Thalidomide without Grünenthal's involvement or authorisation, for example in Spain, Italy and Brazil.
How was Thalidomide developed?
Thalidomide was first synthesised at Grünenthal early in 1954 as a by-product of research into glutamic acid.1 The search for a possible medical application only began afterwards, which was standard practice at the time.
1 Original documents (Laboratory Report of Dr Keller (German), Laboratory Report Dr Kunz (German) and the sworn testimony of Grünenthal researchers Dr Keller and Dr Kunz in the Contergan criminal trial (cf. Dagmar and Karl-Heinz Wenzel (1968): ‘Report and excerpts from the minutes of the 51st to 100th day of the trial’, in: Der Conterganprozess (II); Keller page 56ff, Kunz page 71ff) confirm the year 1954. The patent was also filed in 1954.
How was Thalidomide tested?
Thalidomide was first tested for its pharmacodynamic properties in animal experiments. In addition to acute toxicity, semi-chronic toxicity was also tested. It proved to be a substance with a central depressant effect and simultaneous non-toxicity.
Clinical testing of Thalidomide began in the spring of 1955. The aim was to prove and establish the efficacy, reliability and safety of a new drug under medical supervision.
Our information shows that the development and introduction of Thalidomide corresponded to the state of knowledge and the applicable standards in the pharmaceutical industry at that time. These standards were substantially altered in the subsequent years as a reaction to what was learned from the Thalidomide tragedy.
Was Thalidomide tested on children?
Our information shows that studies were carried out on children before and after the market launch of Thalidomide. Among others, Thalidomide was given to children in the lung sanatorium in Wülfrath-Aprath and the Maria Grünewald sanatorium in Wittlich (Eifel). Unfortunately, such studies were quite common at the time.
We deeply regret having been involved in these drug trials as a company. The methods used to test medicines on children in the 1950s and 1960s are incomprehensible from today's perspective. They do not comply with the current strict ethical and legal rules for drug development and testing.
As the manufacturer, Grünenthal participated in the investigation into the use of Thalidomide at the Maria Grünewald sanatorium and supported the documentation in 2021.
Why was Contergan considered a safer alternative to existing sleep aids or sedatives at the time?
Studies conducted at the time (animal experiments and clinical trials) showed that Thalidomide induces sleepiness and calmness without having acute or semi-chronic toxic effects. Furthermore, it was not possible to administer a lethal dose of the substance to test animals. Since all other sleeping pills commonly used at the time, especially barbiturates, could lead to death in the event of an overdose, Thalidomide was considered a safe alternative.
Why was its effect on unborn children not investigated?
In the 1950s, it was not common practice to test an active ingredient for its potential to harm unborn life. At that time knowledge about the safety of medicines was not as advanced, as it is today. Legal guidelines and scientific standards for testing on pregnant animals were only developed after the tragedy.
When was Thalidomide taken off the market?
On Monday, 27 November 1961, Grünenthal withdrew the drug from the German market and informed its international licensing and distribution partners of this step accordingly. The responsible German health authority had already been informed of this decision on 26 November. The market withdrawal took place 12 days after Dr Widukind Lenz first indicated that Thalidomide might be the cause of malformations in newborn babies.
How was the teratogenic effect of Thalidomide discovered?
The detection of the teratogenic effect of Thalidomide is inseparably linked with the doctors Widukind Lenz and William McBride. Both had observed a noticeable increase in severe malformations in newborns at their clinics and attempted to find the causes. Independently of each other, in mid-November 1961 they suspected that Thalidomide use was the possible cause.
Lenz informed Grünenthal of his observations by telephone on 15 November and explained them in several conversations with the company and health authorities over the following days. McBride reported his suspicion to the local Australian organisation of the licensee Distillers. The latter informed Grünenthal on 24 November 1961. Their reports led to the product being withdrawn from the market on 27 November 1961.
How many children worldwide were harmed by Thalidomide?
The German Federal Contergan Foundation estimates that around 10,000 children worldwide were born with malformations attributable to Thalidomide, 5,000 of them in Germany.1 Around half of them died at or shortly after birth. More than 2,000 affected individuals still live in Germany today. International figures have not been collected by authorities.
1 Conterganstiftung, available at: https://www.contergan-infoportal.de/stiftung/historie/contergan-zeitstrahl/ (in German) under the date 27 November 1961
Was Thalidomide developed during the Nazi era in Germany?
No. Laboratory reports and sworn witness statements prove that Thalidomide was first synthesised by Grünenthal in early 1954 as a by-product of research into glutamic acid.1,2,3 The first patent for Thalidomide was also only filed in May 1954.4 As a comprehensive scientific study commissioned by the state of North Rhine-Westphalia shows, there is no proof to support any claims that Thalidomide was developed during the Nazi era and/ or tested in concentration camps.5
Where do the Nazi speculations come from?
As is the case for many other companies, Grünenthal employed people in the post-war period who had previously held positions within the NSDAP [National Socialist German Workers' Party].
Some conspiracy theorists have concluded that Thalidomide was developed during the Nazi era by Nazi chemists and was tested on concentration camp prisoners as an antidote to chemical warfare agents. There is no reasonable evidence for these speculations.5 We examine two repeatedly expressed theories in greater detail below:
- There is a rumour that Thalidomide was developed before 1954, in the era of the Third Reich. Original documents1, 2 and the witness testimony under oath of Grünenthal researchers Dr Kunz and Dr Keller in the Thalidomide trials4 prove, however, that the two scientists developed the active substance Thalidomide in the Grünenthal lab in 1954. The first patent was applied for in 1954.
- Similarly, attempts are repeatedly made to create a link between the development of the active substance Thalidomide and the Nazi past of Dr Otto Ambros, later a member of the Advisory Board. However, Dr Ambros was never an employee of the Grünenthal company. He joined the Grünenthal Advisory Board in 1972, 11 years after Contergan was withdrawn from the market.
In a research report that appeared in 2016, historian Dr Niklas Lenhard-Schramm investigated a possible connection between Thalidomide and the Third Reich, as well as the plausibility of the theories presented. He concluded that the conspiracy theory allegations that Thalidomide had already been developed before 1954 lacked credible evidence.5
1 Laboratory Report Dr Keller (German)
2 Laboratory Report Dr Kunz (German)
3 Dagmar and Karl-Heinz Wenzel (1968): “Bericht und Protokollauszüge vom 51.-100. Verhandlungstag”, in: Der Conterganprozess (II); Keller page 56ff, Kunz page 71ff.
4 Certificate Granting the Patent for Thalidomide (1954) (German)
5 Niklas Lenhard-Schramm (2016): „Die Haltung des Landes Nordrhein-Westfalen zu Contergan und den Folgen“, Forschungsbericht der WWU Münster für das Ministerium für Gesundheit, Emanzipation, Pflege und Alter des Landes Nordrhein-Westfalen (Research report by the University of Münster for the Ministry of Health, Emancipation, Care and Ageing of the State of North Rhine-Westphalia), page 26f.
Historical review
What was the ‘Thalidomide trial’?
The ‘Thalidomide trial’ was a criminal proceeding against nine senior Grünenthal employees. The aim was to determine whether the defendants – through their actions or lack thereof – were culpably responsible for causing nerve damage in adults and malformations in children in the womb. Whether the affected families were entitled to compensation would have had to be clarified in separate civil proceedings.
The trial began on 27 May 1968 in Alsdorf, Germany, before the First Grand Criminal Chamber of the Aachen Regional Court and was discontinued by the court two and a half years later, on 18 December 1970. It lasted a total of 283 session days and was long considered the most complex criminal proceedings in German legal history.
Why was the Thalidomide-trial discontinued?
The criminal proceedings were terminated without a verdict in December 1970 because the court assumed that the individual guilt of the defendants would be considered minor in the event of a conviction. In the 100-page discontinuation order substantiating the decision, the court stated that continuing the criminal proceedings would be disproportionate and cited two reasons related to the malformations:
- Even in the hypothetical case that, after an orderly completion of the proceedings, misconduct by the accused had been found, the individual culpability of the accused would have been considered minor, despite the serious consequences. Among other factors, the Court took into consideration that there had been no explicit advertising for the use of Thalidomide during pregnancy. In addition, the company withdrew its Thalidomide-containing products just a relatively short time after Dr Lenz expressed his suspicions for the first time.
- Furthermore, it was no longer necessary to continue the criminal proceedings for overriding reasons (designated as in “the public interest” in the German Code of Criminal Proceedings). The Court referred to the fact that Grünenthal and the attorneys for the affected families had already reached a settlement in April 1970 in which Grünenthal agreed to pay 100 million German marks.
Regarding the side effect of polyneuritis, it found misconduct and explained its reasoning as follows: It was proven that taking Thalidomide could result in nerve damage (Polyneuritis). With regard to this nerve damage, Grünenthal had not met the requirements for a proper, conscientious pharmaceutical manufacturer.
Additional explanation regarding compensation
Criminal proceedings in Germany do not determine liability for damages. Any compensation claims against the company would have had to be asserted by the affected families in separate civil proceedings. More years would have passed before a final clarification. Together with the affected families, Grünenthal found a solution outside of the Thalidomide trial. On 10 April 1970, long before the termination of the proceedings, the affected families reached an out-of-court settlement with Grünenthal through their attorneys. The most important result of the settlement was the commitment by Grünenthal to pay 100 million German marks to support affected children.
What support payment did Grünenthal provide?
Grünenthal contributed 110 million German marks (100 million plus 10 million in interest) to support the affected children to what is now the German Federal Contergan Foundation. In April 1970 – long before the end of the criminal proceedings – Grünenthal reached an out-of-court settlement with the lawyers representing the affected families, agreeing to this payment. The German federal government contributed an additional 100 million German marks to the Foundation’s endowment fund. As a result, the claims from the settlement were replaced by lifelong support payments provided by the Contergan Foundation. To date it has supported Thalidomide-affected people in more than 40 countries (for example, in Brazil, Ireland and Spain).
In 2009, Grünenthal voluntarily paid a further €50 million into the Contergan Foundation, which has been used for annual special payments to those affected.
In addition, since 2012, the Grünenthal Foundation for the Support of Thalidomide-Affected People has offered in-kind support for home modifications and personal mobility. These benefits have been used in more than 5,300 cases to date (as of October 2025).
Was there any political interference in the ‘Thalidomide trial’?
No, this allegation is false.
A research report by the historian Dr Lenhard-Schramm, which the State of North Rhine-Westphalia ordered, confirmed in 2016 that the allegations about political influence were based on falsely dated documents and intentional misrepresentations.
- The decision to discontinue the proceedings was made by the Grand Criminal Chamber of the Aachen Regional Court, which consisted of five independent judges – not by the Public Prosecutor’s Office. This also refutes the allegation that the state government at the time exerted improper influence on the Public Prosecutor’s Office under its authority.
- Beyond that, the court made its decision in public proceedings that were followed very intently by the public and the media. Finally, the court explained its decision to terminate the proceedings in a public hearing and justified its decision in a document of almost 100 pages.
How did the Thalidomide tragedy change the way medications are handled?
As a consequence of the Thalidomide tragedy, laws were introduced worldwide to improve the approval and monitoring of medications. In Germany, for instance, a new Medicinal Products Act came into force in 1978, establishing for the first time a uniform and comprehensive process for drug development and control. Comparable laws and regulations were put into place in most other countries. Since then, manufacturers are required to prove, in pharmacological and clinical trials, that their medications are high-quality, safe and effective.
Steps towards reconciliation
Has Grünenthal or the owning family apologised to those affected?
Former Grünenthal CEO Harald Stock publicly apologised for the company’s long silence during the unveiling of a Thalidomide memorial in Stolberg, Germany, in August 2012.
Dr Michael Wirtz, shareholder of Grünenthal, apologised to those affected and their families on behalf of his family. This took place in November 2021 during a personal meeting with Georg Löwenhauser, then chairman of the German Federal Association of Thalidomide Victims.
What is the Grünenthal Foundation for the Support of Thalidomide-Affected People?
The Grünenthal Foundation for the Support of Thalidomide-Affected People was established in 2012 to sustainably and quickly improve the individual living situation of people affected by Thalidomide. It funds in-kind support such as adaptations to kitchens, bathrooms and vehicles, as well as personal assistance, helping affected individuals to lead lives that are as self-determined and fulfilling as possible.
The Foundation focuses its support where it can make the greatest difference: the home environment, assistance with daily living and mobility outside the home. In doing so, it complements the monthly Thalidomide pension provided by the German Federal Contergan Foundation.
What is the Dialogue Forum?
The Dialogue Forum was established in 2023 by the Grünenthal Foundation and the German Federal Association of Thalidomide Victims. Its purpose is to provide a fixed framework for dialogue between affected individuals and the Grünenthal Foundation, to further develop support services, and to jointly implement long-term projects that sustainably improve the quality of life of those affected.
Support today
What support do people affected by Thalidomide receive today?
For people who were harmed by Thalidomide-containing products, several forms of support are available today. These vary from country to country:
Distribution by Grünenthal and partners
In countries where Grünenthal or its former distribution partners sold Thalidomide-containing products, affected individuals are eligible for financial support through the German Federal Contergan Foundation. The monthly Contergan pension amounts to a maximum of €10,017 per month (as of 2025), depending on the severity of the disability. This applies not only to Germany, but also to affected individuals in more than 40 other countries, including Belgium, Austria, Chile and Brazil (as of April 2023).
Distribution by licensees
In countries where licensees marketed their own Thalidomide-containing products, these companies provide financial support, sometimes together with the local government. Such arrangements exist, for instance, in Australia, New Zealand, the United Kingdom and Sweden.
Production and commercialisation without Grünenthal’s authorisation
In countries where other companies independently produced and marketed Thalidomide containing products without a license or permission from Grünenthal, affected individuals are generally supported by the respective government, such as in Italy and Spain.
What is the Contergan Foundation?
The Contergan Foundation was established in 1972. It provides financial assistance, such as monthly pensions and an annual lump-sum payment from the so-called Special Needs Fund, which is provided by the German federal government. As a public-law foundation of the Federal Republic of Germany, it is supervised by the Federal Ministry for Family Affairs, Senior Citizens, Women and Youth (BMFSFJ) and operates independently of Grünenthal.
When the Foundation was created, Grünenthal paid 110 million German marks into the Foundation as part of an out-of-court settlement with affected families. In 2009, Grünenthal voluntarily contributed an additional €50 million to help improve the daily living conditions of people affected by Thalidomide.
The active substance Thalidomide
What is the chemical composition of Thalidomide?
Thalidomide is a derivative of glutamic acid. It is a crystalline solid, easily soluble in water, with the structural formula C13H10N2O4.
The chemical bond in Thalidomide is chiral. That means it can come in two forms known as enantiomers. As was later discovered, one of these enantiomers is teratogenic and causes deformities in embryos.
Later research has shown, however, that the two forms (enantiomers) convert into each other in the body within a few hours. Even if only the non-teratogenic form is administered, both forms are present again in the body within a few hours. In other words, administering the non-teratogenic form cannot prevent the teratogenic effect of Thalidomide.
How does Thalidomide work?
At the time, Thalidomide was identified as having calming and sleep-inducing effects. Today, it is also known to have anti-inflammatory properties and to inhibit the growth of certain cancer cells.
Simply put, it appears to imitate one of the body's messengers that inhibits the transfer of information between nerve cells in the body. The brain, therefore, receives fewer signals. This has a relaxing and sleep-inducing effect on the body.1 At the same time, researchers observed that it was impossible to administer a lethal – and therefore fatal – dose to test animals. Since an overdose of all other sleep aids available at that time could lead to death, Thalidomide was considered an important discovery.
1 https://www.netdoktor.de/medikamente/thalidomid/ (in German)
What are Thalidomide’s side effects?
It was discovered that the substance Thalidomide could cause severe side effects, including deformities. Below, we provide more precise information on some of the side effects of Thalidomide.
Teratogenicity (malformations in unborn children)
If Thalidomide is taken during pregnancy between the 34th and 50th day following the first day of the last menstrual cycle, it leads to deformities including:
- Complete absence or shortening of arms and legs.
- Deformities of the hands and feet.
- Deformities of the hips, digestive tract and genitals.
- Deformities or complete absence of the outer ear.
Polyneuritis (nerve damage)
Thalidomide can cause polyneuritis, an inflammatory disease of the nervous system, in people who use the drug. Symptoms include a sensation of numbness in the tips of the fingers and feet. It can also be very painful. In the case of longer-lasting complaints, polyneuritis also leads to a change in the nerve tissue that can be demonstrated by pathology.
Mechanism of action: How are birth defects caused by Thalidomide (teratogenic effect)?
According to the current state of knowledge, Thalidomide causes deformities because, as a binding link, it bonds specific proteins in a child’s body that control, among other things, the formation of the extremities. This bond prevents a child’s body from being able to develop further.
How does modern science explain the action of Thalidomide?
Every cell in the human body contains proteins.1 They serve as molecular ‘tools’ and can carry out various actions such as switching genes on and off, enabling cell movements or acting as messengers.
Three types of proteins play a role in the mechanism of action of Thalidomide2:
- The protein cereblon can attract other proteins, almost like a magnet3 These proteins are then ‘marked’ by cereblon and broken down (destroyed).4
- The proteins Sall 4 and p63 are known as transcription factors. They can turn genes on and off like a switch. Sall 4 and p63 control growth, and the development of extremities and specific organs in a child's body.
The structures of cereblon and Sall 4 or p63 are so different that they do not fit together in their original states. They exist alongside each other. In this state, Sall 4 and p63 can stimulate the growth of extremities and control the formation of organs.
If Thalidomide is taken during a specific period in pregnancy, the active substance can reach the child’s body through the mother’s metabolism. Once it gets to this point, Thalidomide first docks to cereblon. At this point, a partially different novel structure is formed that can dock with Sall 4 and p63.
As soon as Sall 4 and p63 dock to the cereblon-Thalidomide complex, cereblon can mark the two other proteins and thus signal to the body that they should be broken down. With the elimination of these two proteins, the signal that stimulates the growth of extremities and specific organs in the child’s body is also lost. Depending on when this mechanism is triggered, the child's extremities are not formed at all or are formed incompletely.
1 A protein is a biological macromolecule that can contain several hundred amino acids, which are joined together by peptide bonds. Cereblon contains around 440 amino acids, for example.
2 The p63 proteins are ∆Np63α and TAp63α. The breakdown of the protein ∆Np63α causes damage to the extremities, while the breakdown of the protein TAp63α is responsible for damage to the ears. (Nature Chemical BIOLOGY | VOL 15 | NOVEMBER 2019 | 1077–1084 https://www.nature.com/articles/s41589-019-0366-7 (study published in Nature Chemical Biology)).
3 Cereblon acts as a substrate receptor within the E3-ubiquitin-ligase family.
4 Cereblon is part of the E3-ubiquitin family. Every E3-ubiquitin-ligase can mark certain proteins with ubiquitin, which signalises to the cells that this marked protein should be broken down or destroyed. This marks proteins that contain errors or that have changed. This mechanism manages the life cycle of proteins in this way.
Since when is Thalidomide’s mechanism of action known?
The mechanism of action of Thalidomide, and thus the explanation of why these deformities occurred, remained unknown for decades. The basis for clarifying the mechanism of action was presented by the working teams of Takumi Ito and Hideki Ando from the Tokyo Institute of Technology, as well as by Yamaguchi at the Tokyo Medical University, among others, in 2010.1 This knowledge was supplemented by various international research teams. New findings are being developed even today.2
1 Takumi Ito, Hideki Ando et al (2010): “Identification of a Primary Target of Thalidomide Teratogenicity”, in: Science (327 / 5971), S.1345-1350, available at https://science.sciencemag.org/content/327/5971/1345
2 Tomoko Asatsuma-Okumura, Hideki AndoNature et al (2019): “p63 is a cereblon substrate involved in thalidomide teratogenicity”, in: Nature Chemical Biology (15), S. 1077–1084, available at https://www.nature.com/articles/s41589-019-0366-7
Is Thalidomide still used today?
Research is still being conducted on Thalidomide. It was found that Thalidomide shows favourable properties in severe diseases, such as leprosy, bone marrow cancer and some autoimmune disease.1,2,3 The product may be prescribed and dispensed only in accordance with a special programme to prevent deformities in unborn children.4
Grünenthal no longer produces any Thalidomide-containing products.
1 https://www.emedicinehealth.com/drug-thalidomide/article_em.htm
2 David Millrine, Tadamitsu Kishimoto (2017): “A Brighter Side to Thalidomide: Its Potential Use in Immunological Disorders”, in: Trends in Molecular Medicine, (23 / 4), S. 348ff, available at https://www.cell.com/trends/molecular-medicine/abstract/S1471-4914(17)30025-4
3 https://www.netdoktor.de/medikamente/thalidomid (in German)
4 https://www.ema.europa.eu/en/medicines/human/EPAR/thalidomide-bms
Does Grünenthal still produce any Thalidomide-containing products?
Grünenthal no longer produces any Thalidomide-containing products.
Thalidomide is, however, relatively easy to create and is no longer protected by Grünenthal patents. Grünenthal has no connection to third parties who offer Thalidomide-containing products. Of course, science, industry and regulatory authorities now know about the severe side effects Thalidomide can produce. The active substance’s manufacture and use are therefore subject to strict regulations.